1. Field of the Invention
The present invention relates to fuel gas supply equipment which serves to supply a gas burner with liquefied petroleum gas contained within a gas container and which is provided with a filter for suppressing an abnormal offensive odor of the gas.
2. Background of the Prior Art
Generally, liquefied petroleum gas (simply referred to as LP gas, hereinafter), such as propane gas and the like, is taken out of the gas container through its gas outlet in a gaseous state and then the pressure thereof is reduced to a small pressure of ab. 300 mmAq through a pressure regulating means so that the gas can be supplied to a gas burner such as a portable gas cooking heater or a gas stove.
To LP gas of this kind, there is usually added an extremely small quantity of a smelly agent (for example, an agent of mercaptan series) which gives off an offensive odor, so that a gas leak accident brought about by the fire going-out in the gas burner can be noticed readily. The smelly agent is selected from materials that are harder to gasify than the LP gas in order to remain in the gas throughout the entire period of LP gas supply from the gas container. Thereby, the offensive odor can be noticed when the LP gas leaks into the atmosphere even in the volume ratio of ab.1/1000.
When the gas burner is lighted, a very small quantity of the unburned gas tend to be discharged into the atmosphere between from the opening of a fuel cock to the completion of lighting. Also at the time of extinguishing of the gas burner, a very small quantity of unburned gas remaining in the burner after the closing of the fuel cock tends to be discharged into the atmosphere.
These very small quantities of unburned gases do not give off offensive odors so strong as to hurt somebody's feelings while the liquid portion of the LP gas remains substantially within the gas container, while the liquid portion of the LP gas remains within the gas container, the LP gas and the smelly agent are kept in a proper mixed condition, but, the concentration of the smelly agent mixed with the gas to be supplied to the gas burner is increased abnormally because the concentration of the smelly agent (which is harder to gasify than the LP gas) is increased as the residual liquid portion of the LP gas within gas container is descreased by the consumption thereof.